North Korea on Tuesday rejected UN condemnation of its rocket launch and said it would no longer adhere to an agreement with the United States to freeze its nuclear and missile programmes.

"We resolutely and totally reject the unreasonable behaviour of the UN Security Council to violate the DPRK's (North Korea's) legitimate right to launch satellites," the foreign ministry said in a statement carried by state media.

The statement came after the Security Council ordered tightened sanctions on North Korea over its failed rocket launch Friday and warned of new action if the isolated state stages a nuclear test.

The 15-member council -- including the North's closest ally China -- "strongly condemned" the launch in a statement that highlighted "grave security concerns" in Asia.

North Korea claimed the launch was to put a satellite into orbit as part of celebrations to mark the centenary of the birth of the country's founder Kim Il-Sung, as his young grandson Kim Jong-Un takes over the reins of power.

The United States and its allies, however, said it was a disguised long-range ballistic missile test banned under UN resolutions.

"We will expand and strengthen space development institutions and continue launching a variety of working satellites needed for economic development of the country," the North Korean foreign ministry said.

"Nothing can stand in the way of (North Korea)'s space development for peaceful purposes."

It also accused the United States of breaching a February deal in which Washington had promised 240,000 tonnes of food aid for North Korea in exchange for promises that it would suspend enrichment of uranium and cancel nuclear and missile tests.

Washington has suspended the deal.

"As the US violated the February 29 (North Korea)-US agreement through its undisguised hostile acts, we will no longer be bound to it. We have thus become able to take necessary retaliatory measures, free from the agreement," it said, without specifying exactly what it meant.

"The US will be held wholly accountable for all the ensuing consequences. Peace is very dear for us but the dignity of the nation and the sovereignty of the country are dearer for us."

The United States said North Korea remained bound not to conduct a feared third nuclear test.

State Department spokesman Mark Toner said North Korea was still obliged to comply with UN Security Council resolutions that demanded no further nuclear tests after the regime donated atomic bombs in 2006 and 2009.

"We believe that it's not just the commitments that North Korea made on Leap Day, but also existing Security Council resolutions that hold North Korea to the pledge not to conduct any nuclear tests," Toner told reporters.

At the meeting in New York on Monday the Security Council ordered a tightening of sanctions imposed after North Korea's nuclear tests.

The Council said the launch of the rocket, which disintegrated over the Yellow Sea shortly after blast off, was a "serious violation" of UN resolutions and "strongly condemned" the act.

It demanded that North Korea hold back from new launches "using ballistic missile technology" and suspend "all activities related to its ballistic missile programme" and keep to its promised "moratorium on missile launches".

"The Security Council expresses its determination to take action accordingly in the event of a further DPRK (North Korean) launch or nuclear test," said the statement.

North Korea has been developing missiles for decades both for what it terms self-defence and as a lucrative export commodity.

The UN condemnation came as Pyongyang reportedly said it would not allow International Atomic Energy Agency inspectors to examine its nuclear programme -- a key part of the February deal.

Japanese and South Korean analysts and officials say satellite imagery showing preparations at the North Korean town of Punggye-ri -- where nuclear blasts were staged in 2006 and 2009 -- suggest a test could be imminent.

burs/mtp/ach